Field of the Disclosure
The present invention relates generally to image sensors. More specifically, examples of the present invention are related to circuits that control image sensors.
Background
Image sensors have become ubiquitous. They are widely used in digital cameras, cellular phones, security cameras, as well as, medical, automobile, and other applications. The technology used to manufacture image sensors, and in particular, complementary metal-oxide-semiconductor (CMOS) image sensors, has continued to advance at great pace. For example, the demands of higher resolution and higher quality image sensors have encouraged the further advancement of these image sensors.
In a conventional CMOS active pixel sensor, image charge is accumulated in a photodiode in response to incident light is then transferred from a photosensitive device (e.g., a photodiode) and is converted to a voltage signal inside the pixel circuit on a floating diffusion node. The image charge on the floating diffusion may then be amplified and then read out and sampled through a bitline by readout circuitry.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.